Ground clamp adaptor



FIG. 1 is a front perspective view of a ground clamp adaptor showing my new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a front elevational view thereof, the rear elevational view being a mirror image;

FIG. 4 is a left end elevational view thereof;

FIG. 5 is a right end elevational view thereof. 

The ornamental design for a ground clamp adaptor, as shown and described. 